-// Copyright (C) 2007
-// Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
-// Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
+// $Id$
+//
+// Copyright (C) 2007
+// Fraunhofer Institute for Open Communication Systems (FOKUS)
+// Competence Center NETwork research (NET), St. Augustin, GERMANY
// Stefan Bund <g0dil@berlios.de>
//
// This program is free software; you can redistribute it and/or modify
#define IH_PacketParser_ 1
// Custom includes
+#include "../Utils/mpl.hh"
///////////////////////////////ih.p////////////////////////////////////////
# ifndef DOXYGEN
- template <PacketParserBase::size_type i>
- struct Parser_TakeNum {};
-
+ // Use SFINAE to check, if Parser has an integer-valued fixed_bytes member. If not,
+ // 'Parser_TakeNum<Parser::fixed_bytes>' fails and the overload is removed from the overload
+ // set.
template <class Parser>
PacketParserBase::size_type packetParserSize(
- Parser p, int, Parser_TakeNum<Parser::fixed_bytes> * = 0);
+ Parser p, int, senf::mpl::take_uint<Parser::fixed_bytes> * = 0);
+ // An ellipsis is always the worst match. A call 'packetParserSize(p,0) will prefer above
+ // overload if that is not disabled by SFINAE.
template <class Parser>
PacketParserBase::size_type packetParserSize(Parser p, ...);
- template <unsigned n> struct ParserInitBytes_RV { char _[16][n]; };
-
+ // Same as above: This overload is only enabled, if Parser has an integer values 'init_bytes'
+ // member.
template <class Parser>
- ParserInitBytes_RV<1> ParserInitBytes_Choose_(Parser_TakeNum<Parser::init_bytes> *);
-
+ senf::mpl::rv<0> ParserInitBytes_Choose_(senf::mpl::take_uint<Parser::init_bytes> *);
+
template <class Parser>
- ParserInitBytes_RV<2> ParserInitBytes_Choose_(...);
+ senf::mpl::rv<1> ParserInitBytes_Choose_(...);
- template <class Parser, unsigned size>
+ // This version of ParserInitBytes_Choose uses 'Parser::init_bytes' to provide 'value' (via
+ // 'boost::integral_constant')
+ template <class Parser, unsigned _>
struct ParserInitBytes_Choose
: public boost::integral_constant<PacketParserBase::size_type, Parser::init_bytes> {};
-
+ // ^^-- g++ error signaled here:
+ // error: 'fixed_bytes' is not a member of 'some-class-name'
+ //
+ // The 'some-class-name' class (as given in the error message) does not seem to be a parser at
+ // all (it has neither a 'fixed_bytes' nor an 'init_bytes' member).
+ //
+ // Either 'some-class-name' is not the class you wanted to use (it really is no parser) or you
+ // left out either 'init_bytes' or 'fixed_bytes' when defining the parser. This will also
+ // happen, if you forget to call 'SENF_PARSER_FINALIZE()' when defining a composite parser.
+ ///////////////////////////////////////////////////////////////////////////////////////////////
+
+ // If Parser::init_bytes is not defined, this specialization is chosen which instead uses
+ // 'Parser::fixed_bytes'
template <class Parser>
- struct ParserInitBytes_Choose<Parser, sizeof(ParserInitBytes_RV<2>)>
+ struct ParserInitBytes_Choose<Parser, 1>
: public boost::integral_constant<PacketParserBase::size_type, Parser::fixed_bytes> {};
template <class Parser>
struct ParserInitBytes
- : public ParserInitBytes_Choose<Parser, sizeof(ParserInitBytes_Choose_<Parser>(0))> {};
+ : public ParserInitBytes_Choose<Parser,SENF_MPL_RV(ParserInitBytes_Choose_<Parser>(0))> {};
# endif